Typically, telecommunication systems that provide broadband access to customers contain a transceiver such as a residential gateway. The residential gateway consists of a xDSL (any type of digital subscriber line generally communicated over copper lines) modem or xPON (any type of passive optical network generally communicated over optic fibers) interface combined with various local area networking (LAN) technologies to enable sharing the broadband access with other computers or devices within the residence or building. Wireless local area network standards and home phone line networking (HPNA) are examples of such LAN technologies.
A wireless LAN or WLAN is a wireless local area network, which is the linking of two or more computers without using wires. WLAN utilizes spread-spectrum technology based on radio waves to enable communication between devices in a limited area, also known as the basic service set. This gives users the mobility to move around within a broad coverage area and still be coupled to the network. A wireless access point (WAP) provides a wireless LAN by coupling to an Ethernet hub or switch. Each access point is a base station that transmits radio frequency (RF) signals over a radius of some distance.
For a dual frequency band application, the WAP is typically coupled to a dual band antenna with a single feed point to provide the wireless LAN with two frequency bands such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 industrial, scientific, and medical (ISM) RF bands. This necessitates the use of one or more diplexers to combine and separate the signals being sent to and received from the dual band antenna. One dual band antenna design is illustrated in FIG. 1A. This design includes two diplexers, one for the transmitting signals to the antenna and another diplexer for receiving signals from the antenna. However, these diplexers add additional cost and attenuate the desired signals. These diplexers also add design complexity because the diplexers can distort the desired signals.
Other types of antenna designs may include multiple single-band antennas as illustrated in FIG. 1B. This design also includes two diplexers, one for the transmitting signals to the transmit antenna and another diplexer for receiving signals from the receive antenna. These diplexers and multiple antennas add additional cost and require additional space. Diplexers also add design complexity because they can distort the desired signals.